JPH01170727A - Drive force controller for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a vehicle driving force control system in which a throttle valve that is mechanically disconnected from an accelerator operator is controlled to open and close in response to the operation of the accelerator operator. Regarding equipment.

(Prior Art) As a conventional vehicle driving force control device, for example, a device described in Japanese Patent Application Laid-Open No. 60-43133 is known.

This conventional device is an engine output control device for an automobile that controls engine output by changing the amount of fuel supplied to the engine according to the position of the accelerator pedal. Calculating means for calculating the slip rate between the tires and the road surface from the output of the rain detecting means; comparison means for comparing the calculated slip rate with a set slip rate; and a control ratio based on the accelerator pedal position when the calculated slip rate is large. The engine was characterized by a semi-slip control means that outputs a signal that forcibly reduces the fuel supply to the engine in preference to force.

(Problem to be Solved by the Invention) However, in such conventional vehicle driving force control devices, when the set slip rate is exceeded, the fuel supply to the engine is reduced to avoid slip, and the slip rate is reduced. After the slip is avoided, control is performed to return to the state before the slip was avoided, so there is a problem in that the same slip occurs again after the slip is avoided.

Furthermore, when driving on a road with a low friction coefficient where driving wheel slip is likely to occur, a hunting state occurs in which the fuel supply to the engine is repeatedly decreased and increased regardless of accelerator operation, causing jerky vibrations.

In addition, when the slip rate is large, the engine driving force is forcibly controlled in priority to the throttle opening control based on the accelerator pedal position, so during slip prevention control, the correspondence between the accelerator pedal operation and the engine driving force is , and the accelerator operation feels strange.

Therefore, in order to solve these problems, the present applicant previously filed Japanese Patent Application No. 157389/1983.

However, in this prior application, when the slip rate exceeds the set slip rate, based on the control characteristic map at that time,
Since the configuration was such that a map lower than that map was selected, when the slip rate was small, the map would move to a higher rank,
As a result, when the slip ratio becomes large, it is unreasonable to select a lower map based on the map at that time, without taking into account engine response delay and the like.

In other words, even though the current map has no meaning, selecting a new map based on the current map may lead to poor acceleration or reoccurrence of slipping, depending on the settings.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and to achieve this purpose, the present invention employs the following solving means.

The solving means of the first invention will be explained with reference to the claim correspondence diagram shown in FIG. Slip ratio calculation means C for calculating a slip ratio, accelerator operation amount detection means d for detecting an accelerator operation amount for an accelerator operator, and actual throttle opening value detection means e for detecting an actual throttle opening value of a throttle valve. , a map setting means f that sets a plurality of control characteristic maps of the relationship between the throttle opening degree and the accelerator operation amount; The map moves to a higher level control characteristic map that increases the throttle opening increase ratio, and each time the slip rate exceeds the set slip rate, the throttle opening increase ratio relative to the accelerator operation amount is lowered from the control characteristic map a predetermined time ago. a map selection means g for selecting a lower control characteristic map, and a target throttle opening value setting means for determining a target throttle opening value based on the control characteristic map selected by the map selection means g and the accelerator operation amount. and,
The present invention is characterized in that it comprises a throttle valve opening/closing control means j for outputting a control signal to the throttle actuator i to make the actual throttle opening value match the target throttle opening value.

Further, in the second invention, an engine rotation speed detection means k is added as a detection means, and the map selection means g is selected every time the slip rate exceeds the set slip rate, before a set time determined by the engine rotation speed at that time. This is a means of selecting a lower control characteristic map that has a lower increase ratio of the throttle opening to the accelerator operation amount than the control characteristic map of the previous control characteristic map.

Further, in the third invention, a gear ratio detection means β is added as a detection means, and the map selection means g is controlled before a set time determined by the gear ratio at that time every time the slip ratio exceeds the set slip ratio. The method is used to select a lower control characteristic map that has a lower increase ratio of throttle opening to accelerator operation amount than the characteristic map.

(Function) If drive wheel slip occurs when driving on a road with a low friction coefficient or during acceleration driving on a road with a high friction coefficient, the control is performed a predetermined period of time each time the slip rate exceeds the set slip rate. A lower control characteristic map that lowers the increase ratio of the throttle opening to the accelerator operation amount is selected from the characteristic map.
Since the throttle valve operates in the closing direction, the driving force is reduced and drive wheel slip is prevented.

In other words, this map lowering control estimates that the current slip has occurred due to the control characteristic map position a predetermined time ago due to engine response delay, and uses that control characteristic map as a reference to shift to a lower map. It is possible to select the throttle valve opening degree that matches the road surface friction coefficient.

Note that how far back the control characteristic map should be based on the current characteristics depends on the engine speed and gear ratio, which are closely related to engine response delay, as in the second and a aspects of the invention. When this is set, the past control characteristic map position where the current slip occurred can be estimated more accurately than when it is set a uniquely determined predetermined time ago.

After the map drop control as described above is performed,
Since the lower control characteristic map is maintained as it is until the predetermined map ascending conditions are satisfied or the slip ratio exceeds the newly set slip ratio, drive wheel slip immediately occurs even after drive wheel slip has been avoided. The driving force does not return to the previous driving force level, and re-slip is prevented.Furthermore, in the case of drive wheel slip, the throttle opening is reduced to reduce the driving force, so the driving force is reduced. There is no occurrence of hunting due to increase or decrease in

Furthermore, even during slip prevention control, the throttle opening degree is controlled in accordance with the amount of accelerator operation based on the control characteristic map selected by the map drop, so that the accelerator operation does not feel strange.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a driving force control device applied to a rear wheel drive vehicle will be taken as an example.

First, the configuration of the embodiment will be explained.

As shown in FIG. 2, a power train P of a rear wheel drive vehicle to which the driving force control device A of the embodiment is applied includes an engine 10
, transmission 11, propeller shaft 12, rear differential 13, rear drive shaft 14
．． 15, rear wheels 16.17.

Front wheels 18,19 are non-drive wheels.

The driving force control device A of the embodiment includes an accelerator pedal 20 that is an accelerator operator, and a throttle valve 22 provided in a throttle chamber 21 that is an intake system of the engine 10.
A control device is provided between the accelerator pedal 20 and the throttle valve 22 in place of a mechanical connection means such as an accelerator control wire, and the rear wheel rotation speed sensor 30 is used as an input sensor. Right front wheel rotation speed sensor 31. It is provided with a left front rotation speed sensor 32 and an accelerator potentiometer 33, a throttle valve control circuit 34 as a calculation processing means, and a step motor 35 as a throttle actuator.

The rear wheel rotation speed sensor 30 is a drive wheel speed detection means,
It is provided at the input shaft portion of the rear differential 13 and outputs a rear wheel rotation signal (vr) according to the rear wheel rotation speed VR.

Note that a photosensitive sensor, a magnetic sensor, or the like is used as the rear wheel rotation speed sensor 30, and when a pulse signal is output as the rear wheel rotation signal (vr), an input interface in the throttle valve control circuit 34 is used. Regarding the circuit 3411,
The F/V converter converts the voltage into a voltage according to the frequency of the pulse signal, and the A/D converter converts the voltage value into a digital value, which is read into the CPU 342 and memory 343.

The right front wheel rotation speed sensor 31 and the left front wheel rotation speed sensor 3
Reference numeral 2 denotes a vehicle speed detection means, which is provided at each axle portion of the front wheels 18 and 19, and which outputs a right front wheel rotation signal (v
f r) and a left front wheel rotation signal (vfffl).

Note that the signal conversion for reading the output signals from both front wheel rotation speed sensors 31 and 32 by the CPU 342 of the throttle valve control circuit 34 is performed in the same manner as the rear wheel rotation speed sensor 30.

The accelerator potentiometer 33 is a means for detecting the absolute accelerator operation amount 2, is provided at the position of the accelerator pedal 20, and outputs an absolute accelerator operation amount signal (I2) corresponding to the absolute accelerator operation amount 2.

Note that since the output signal from the accelerator potentiometer 33 is an analog signal based on a voltage value, it is converted into a digital value by the A/D converter of the input interface circuit 341 and read into the CPU 342 and the memory 343.

The throttle valve control circuit 34 processes input information from the input sensor and information temporarily or pre-stored in the memory 343 according to a predetermined arithmetic processing procedure, and controls the step motor 35, which is a throttle actuator.
An electronic circuit centered on a microcomputer that outputs a pulse control signal (C) to the input interface circuit 341. CPU (central processing unit) 342, memory (RAM).

ROM) 343 and an output interface circuit 344.

As shown in FIG. 3, the memory 343 that functions as a map setting means for the throttle valve control circuit 34 includes
Region control characteristic maps #0 to #7 having eight types of upper and lower limits are set as control characteristic maps of throttle opening θ with respect to absolute accelerator operation amount 2, and each map #
0 to #7 correspond to the throttle opening degree θ that generates the maximum driving force when the road surface friction coefficient μ is shown in Table 1 below.

Note that the upper limit of each map #O to #7 is the line connecting the maximum throttle opening at 3/4 of the absolute accelerator operation amount and the zero reference point, and the line connecting the throttle opening at the absolute accelerator operation amount of 3/4 to 4/4. The lower limit is formed by a line connecting the maximum throttle opening at 4/4 of the absolute accelerator operation amount and the zero reference point.

In addition, the memory 343 of the throttle valve control circuit 34 has the following information:
As shown in FIG. 4, the relationship between the relative accelerator operation amount Δβ and the throttle opening change amount Δθ is set as a cubic curve characteristic.

The throttle valve control circuit 34 includes slip ratio calculation means, actual throttle opening detection means, map selection means, target throttle opening value setting means, and throttle valve opening/closing control means described in the claims. .

The actual throttle opening detection means has an internal circuit configuration that receives a 5TEP command from the CPU 342 of the throttle valve control circuit 34 to the output interface circuit 344 in the memory 343, and writes and counts the number of 5TEP in the memory 343. and reads the actual throttle opening value θ according to a read command from the CPU 342. is the CPU at any time
342.

Further, the map selection means includes a map up selection means and a map down selection means.

The step motor 35 is an actuator that opens and closes the throttle valve 22, and includes a rotor and a plurality of stators having excitation windings, and rotates in the forward and reverse directions by applying pulses to the excitation windings. Rotate one step at a time.

Next, the operation of the first embodiment will be explained.

First, the flow of the throttle valve opening/closing control operation in the CPU 342 will be described with reference to the main routine flowchart shown in FIG. 5 and the subroutine flowchart shown in FIG.

It should be noted that the processing in the main routine of FIG.
0 m5ec), and the processing in the subroutine shown in FIG. 6 is started as appropriate within the main routine according to the signal output cycle to the step motor 35 determined by this fixed time interrupt. Oci
This is interrupt processing.

(B) Initial Settings The main routine shown in Figure 5 starts when the engine key is inserted into the key cylinder and the ignition switch is turned from OFF to ON. A determination is made (step 100), and the process proceeds to the next initialization step 101.

In this initialization step 101, MAPFLG
Set MAPFLG=O, as well as other FLGs and reference value β. . , θoo, etc. are all cleared.

(b) Slip ratio calculation processing The calculation processing of the slip ratio S between the tire and the road surface is performed in steps 102 to 107.

First, based on the input signals from each rotation speed sensor 30, 31, and 32, the rear wheel rotation speed 3. Right front wheel rotation speed V,
R9 left front rotation speed VFL is read (step 10
2), next, the front wheel rotation speed VF is calculated (step 1
03).

The calculation formula is V F = (Vr R+ VF L
), and is determined by the average value.

Next, the rotation speed VR of the rear wheel, which is the drive shaft, is 40 km/h.
It is determined whether or not V7≧4 (step 104).
In the case of 0 (km/h), the process proceeds to step 105, and in this step lσ5, the slip ratio S is calculated.

be.

Further, in step 104, VR<40 (km/h)
If it is determined that
, IV, ) is calculated (step 106), and the slip ratio S is set according to the calculated front and rear wheel rotational speed difference ΔV (step 107).

Therefore, the slip ratio S obtained in step 105 or step 107 is graphed as shown in FIG. 7, and this slip ratio S is changed to each set slip ratio S0°S, , S, is the threshold value for comparison.

(c) Control Information Setting Process The control information setting process used in the map selection process and the accelerator work determination process, which will be described later, is performed in steps 150 to 154 and steps 251 to 255.

First, the accelerator pedal depression amount sampled in the process two cycles ago and treated as the previous absolute accelerator operation amount I21 in the process one cycle ago is set as the previous absolute accelerator operation amount f22 (step 150). Also, it was sampled in the process one cycle ago, and this time the absolute accelerator operation amount! . The accelerator pedal depression amount treated as 1 is set as the previous absolute accelerator operation amount β1 (step 151). Next, the current accelerator pedal depression amount is the absolute accelerator operation amount this time! . Also, the current throttle valve opening is the actual throttle opening value θ. sampled and read (step 152).

Next, the absolute accelerator operation amount that has already been set! . By subtracting the previous absolute accelerator operation amount I21 from , the current relative accelerator operation amount ΔL, which is the amount of change in the accelerator pedal depression amount from the processing one cycle ago, is calculated (step 153). By subtracting the previous absolute accelerator operation amount β2 from the operation amount β1, the previous relative accelerator operation amount ΔL, which is the amount of change in the amount of accelerator pedal depression that changed from the time of processing two cycles ago to the time of processing one cycle ago, is calculated. (Step 1
54).

In steps 251 to 255, the control characteristic map MAPFLG is recorded and adjusted up to a predetermined time period (here, 600 m5ec ago).

The counter CTR is a counter that determines the number of times MAPFLG is looped in order to store it at a predetermined number of addresses (600m5e:/20m5ec=30 in the example),
After looping between step 251 and step 253 29 times, the process proceeds to step 254 and subsequent steps. In step 252, the address (r (MAPFL
G)+CTRJ) is stored in the memory address +1. Past values of MAPFLG are sequentially stored in the memory at address +1 according to the loop (therefore, the value of MAPFLG 600 m5ec ago, MAPLOLD, used in steps 123.124 and 129.130, which will be described later, is stored at address MAPFLG+30.

In step 254, the contents of address rMAPFLG+30J obtained in the 29th loop of step 252, that is, the value 60On+sec ago of MAPFLG, are converted into MAPFL.
Store in G.

Furthermore, by clearing the counter CTR shown in step 253, MAPOLD is set to r60 once per control cycle.
The value of MAPFLG 0m5ec ago" is rewritten.

(d) Map up selection process This process is performed when the area control characteristic is located in an area control characteristic map lower than the highest area control characteristic map by the map down selection means to be described later.

The map up selection process for selecting a higher region control characteristic map with a higher increase ratio of the throttle opening θ relative to the absolute accelerator operation amount β than the currently selected region control characteristic map includes steps 110 to 119 and steps 161 to 161. This is done in step 163.

First, it is determined whether the current absolute accelerator operation amount 2° is greater than or equal to the high setting accelerator operation amount β□ (step 1
15). In addition, the high setting accelerator operation amount in the first example! 2
When the maximum accelerator operation amount is 1, H is set to 12.4=3/4, which is the kickdown-like area boundary.

Also, this time the absolute accelerator operation amount is 12o, which is the low setting accelerator operation amount! It is determined whether it is greater than or equal to L (step 250). Note that the low setting accelerator operation amount 2L in the first embodiment is l2L=174 as the low accelerator operation area boundary.
It is set to . Then, in step 115, 2゜〈β8
And if it is determined in step 250 that βo>12L (that is, if !L≦β.kl2), it is determined whether the current relative accelerator operation amount ΔL0 is Lo>0, that is, whether the accelerator pedal 20 is depressed It is determined whether it is the time of operation (step 110), and then whether or not the slip rate S is S≦S (for example, S, = 0.1), that is, the set slip rate S. It is determined in the following whether almost no drive shaft slip has occurred (step 11).
1), then the actual throttle opening value θ. is 0°≧0□8, that is, the actual throttle opening value θ. It is determined whether or not is the throttle opening upper limit value θ□8 according to the previously selected region control characteristic map (step 112), and then MAPFLG is determined whether MAPFLG=0, that is, map #l~ which allows map upward movement. #7 is determined (step 113), and only when all of these map up conditions are satisfied, the process proceeds to step 114, and the MA
The PFLG numbers (#l to #7) are lowered by 1 (step 114) and the area control characteristic map is shifted to a map one level higher. Note that the steps 110 to 1 described above
If even one of the map up conditions described in 13 is not satisfied, the area control characteristic map selected at that time is held until all of the new map up conditions are satisfied.

Also, in step 115! . ≧12. If it is determined that the slip rate S is S≦So (for example, 50=0.r
) (step 116), and S≦
When the time is 80, the process proceeds to step 117, where it is determined whether or not the timer is up. If the timer is not up, the process proceeds to step 118, where the timer value is increased. In this way, step 115 → step 116 → step 117
- The flow of step 118 is continuously repeated, and if it is determined that the timer is up in step 117, then in step 161 M A P F L G is
It is determined whether FLG=0, that is, whether the maps #1 to #7 can be ascended, and the step β is determined. ≧9. ．． 4
Then, if S≦So continues for a predetermined time and all the map up conditions of MAPFLG≠0 are satisfied, step 162
Then, the MAPFLG number (#1 to #7) is lowered to the lowest level, and the area control characteristic map is shifted to one level higher. Note that step 119 and step 163 are timer clear steps, and the slip rate S is S>S.
o, and when map up control ends, the timer is cleared for the next timer value count.

Also, the set time T for the timer to expire in the first embodiment. is set to 0.8 sec.

(e) Map drop selection process The map drop selection process of selecting a lower region control characteristic map that has a lower increase ratio of throttle opening θ to absolute accelerator operation amount β than the currently selected region control characteristic map is performed in step 120. ~ is carried out in step 131.

First, the slip rate S and the first set value S, (for example, S, =
O, l) are compared, and S, which is the upper limit for dropping one map
>S, that is, whether or not driving wheel slip has occurred (step 120), SO5,
In this case, proceed to the next step 121 and FLAG −A=
o, and if FLAG-A=O, FLAG-A=1 is set (step 122).
, in the next step 123, MAPFLG's 600m5e
It is determined whether the previous value MAPOLD (step 254) is 7, and if MAPOLD≠7, the condition for dropping one MAP is satisfied, and the number of MAPF LG (#0 to #6) is When the highest value is raised, MAPFL
The data is stored at address G (step 124).

Note that after one map has been dropped in step 124, it is determined in step 120 that S≦51, and the process in step 12 is performed.
5, FLAG-A is set to 0, and
Unless S>S is newly established, the selection process for one missing map is not performed, and the area control characteristic map selected due to one missing map in step 124 is held as is.

However, this is different if the process proceeds from step 121 to step 126 when FLAG-A=1 and the map drop condition of S>52, which will be described later, is satisfied.

Further, when proceeding from the step 124 to the next step 126, the slip ratio S and the second set value S2 (for example, 52=
O-3) is compared, and S
It is determined whether or not O32, that is, whether excessive drive wheel slip has occurred. If S>52, the process proceeds to the next step 127, and it is determined whether FLAG-B=O. FLAG・B in some cases
= 1 (step 128), and the next step 1
29 is the value MAPO 600m5ec before MAPFLG
It is determined whether LD (step 254) is 7, and M
When APOLD≠7, the condition for dropping one map (S>S,
and MAPOLD≠7), MAPO
The LD number (#0 to #6) is raised to the highest level, and the area control characteristic map is moved to a map one level lower, and then MAPOLD.
The value of is stored in MAPFLG (step 130).

Note that after one map has been dropped in step 130, it is determined in step 126 that S≦82, and step 13
1 and is set to FLAG-B=O, and
Unless S>S2 is newly established, the selection process for one missing map is not performed, and the area control characteristic map selected due to one missing map in step 130 is held as is.

(v) In the area control characteristic map setting step 140, the MAP selected by the progress of the above-mentioned map up selection process and map down selection process is performed.
An area control characteristic map with the same number as the FLG number is set.

(g) When the map holding process 12o≦2L, steps 110 to 114 of the map up selection process are bypassed in step 250, so the currently selected area control characteristic map is held as is. Become.

In addition, 2°≦2. When , naturally 2°≦2□, so steps 116 to 119. No signal is input to the other map up selection process in steps 161 to 163.

Further, in step 164, it is determined whether the current absolute accelerator operation amount 2° exceeds the low setting accelerator operation amount I2L, and the current absolute accelerator operation amount 2° is determined to be 0°C. 〉β, the accelerator work judgment process described later in steps 155 to 157 is performed, and 2
When ゜≦12L, no matter how you operate the accelerator, the process proceeds to step 158 and step 159, and the reference value is reached! . . ,
θ. . In order to update the throttle opening degree θ, the throttle opening degree θ is in line with the lower limit of the selected region control characteristic map.

In addition, the low setting accelerator operation amount in the first example! , is set to l2L=l/4 as the boundary of the micro accelerator operation area.

Also, β. When ≦β, steps 110 to 114 of the map up selection process are bypassed in step 250, so the selected area control characteristic map is held as is.

(H) Accelerator work determination process The accelerator work determination process uses constant speed driving when the accelerator is being operated as the standard for determining the relative accelerator operation amount ΔL, so that it can be determined whether or not it is during constant speed driving when the accelerator is being operated. This is the processing performed in steps 155 to 159 based on the information obtained in steps 150 to 154.

First, the judgment logic for accelerator work is that, using the previous relative accelerator operation amount ΔL and the current relative accelerator operation amount ΔL0, the accelerator pedal 2.0 is being operated in the depression direction continuously from the processing two cycles ago. When the acceleration accelerator operation is determined to be (affirmative at step 155, affirmative at step 156), or when the deceleration accelerator operation is subsequently determined to be a return operation (
If the result in step 155 is negative and the result in step 157 is negative, the process proceeds to the next step 160.

Further, when the accelerator pedal 20 is operated to stop and is held at that position (negative in step 155, step 1
57 is affirmative), if the operation direction of the accelerator pedal 20 is switched from the depression direction to the return direction (step 155
(affirmative in step 156, negative in step 156), or vice versa (negative in step 155, affirmative in step 157), the amount of change in the amount of accelerator pedal depression changes from an increase including O to including O. It is determined that the constant speed accelerator operation is decreasing or changing from decreasing to increasing, and the process proceeds to step 158, where the current absolute accelerator operation amount is determined! . is the accelerator operation amount reference value 2°. The process then proceeds to step 159 where the current actual throttle opening value θ is determined. is the throttle opening reference value θ. . is set as .

(S) Relative Accelerator Stroke Calculation Process After the above-mentioned accelerator work determination process is performed, the process proceeds to step 160, where the relative accelerator operation amount ΔL is calculated.

The calculation formula for this relative accelerator operation amount ΔL is ΔL=β. −
2°. Therefore, when accelerating the accelerator or decelerating the accelerator, it is calculated as the accelerator operation change amount from the time when the constant speed traveling accelerator was first performed to the current absolute accelerator operation amount of 2 degrees. Further, when the accelerator is operated for the first time when traveling at a constant speed, ΔL=loo 12oo, and the relative accelerator operation amount L becomes zero.

(J) In the throttle opening change calculation step 170, 〇 is calculated for the throttle opening change based on the relative accelerator operation amount ΔL obtained in step 160 and the ΔL-Δθ characteristic diagram shown in FIG. .

(l) Target throttle opening value setting process The throttle opening reference value θ. 0 and step 170
the plate target throttle opening value θθ obtained from the throttle opening change amount Δθ calculated in step 14;
The area control characteristic map set at 0 and the current absolute accelerator operation amount β. Process of setting the target throttle opening value θ by comparing the throttle opening upper limit value θ□8 and the throttle opening lower limit value θ, 1.1 determined by (or accelerator operation amount reference value!...) is performed in steps 180-185.

First, the plate target throttle opening value θθ is determined in step 180.
is the throttle opening reference value θ. . and the throttle opening change amount Δθ, θθ=θ. . It is determined by +Δθ.

These plate target throttle opening value θθ, throttle opening upper limit value θMAX, and throttle opening lower limit value θ1. In the comparison process with llN, it is first determined whether the temporary target throttle opening value θθ is greater than or equal to the throttle opening upper limit value 0□8 (step 184), and if θθ>θ&lAx, the throttle opening upper limit value θ□8 is determined. is set as the target throttle opening value θ* (step 182). If θθ≦0□8, it is determined whether the temporary target throttle opening value θθ is less than or equal to the throttle opening lower limit value 0141N (step 183
), if θθ<θMIN, the throttle opening lower limit value θ
MIN is set as the target throttle opening value θ (
step 184). Also, θvIN≦θθ≦014AX
In this case, the temporary target throttle opening value θθ is directly set as the target throttle opening value θ* (step 1).
85).

That is, the target throttle opening value θ* is set as a value existing within the region of the selected region control characteristic map.

(w) Throttle valve opening/closing control process Once the target throttle opening value θ* is determined by the target throttle opening value setting process described above, the actual throttle opening value θ
. The process of operating the throttle valve 22 in a direction to make the target throttle opening value θ coincide with the target throttle opening value θ is performed in steps 200 to 202 in the main routine of FIG. 5 and steps 300 to 304 in the subroutine of FIG.

First, the deviation ε is from the target throttle opening value θ* to the actual throttle opening value θ. It is calculated by subtracting (Step 2
00), calculation of the motor speed of the step motor 35 based on the deviation ε obtained by this calculation, forward rotation, reverse rotation,
The determination of retention and furthermore the activation cycle of the oci interrupt routine is determined (step 201).
The oci interrupt routine (FIG. 6) is activated in accordance with the operation control details of the step motor 35 set in step 202.

Next, a flowchart of the oci interrupt routine will be described with reference to FIG.

First, it is determined whether it is time to output a holding command to maintain the state of the step motor 35 (step 300).
), when the holding command is output, the step motor 3
The stator side excitation state of No. 5 is maintained (step 301).

In addition, when the holding command is not output, the step motor 3
It is determined whether or not it is time to output a reversal command to reverse the rotation speed (step 302), and when the reversal command is output, 5TEP should be set to 5TEP-1 (step 303).
), 5TEP-1 is output to the step motor 35 (step 301). Furthermore, when outputting a normal rotation command to rotate the step motor 35 in the normal direction, 5T
Set EP to 5TEP + 1 (step 304),
The pulse signal that gives 5TEP+1 is sent to step motor 3.
5 (step 3゜l).

Note that this oci interrupt routine includes step 20 described above.
It is repeated within the main routine startup cycle according to the startup cycle set in step 1.

Next, regarding the map up control operation, please refer to the patent application filed in 1986-16.
The description in No. 2248 will be omitted, and the map drop control will be described here with reference to the time chart shown in FIG.

Initially, area control characteristic map #7 is selected, but since the state of slip rate S≦S, (S, = 0.1) continues, steps 116 to 118 and steps 161 to 163 are performed. Assume that the map up conditions are satisfied and the area control characteristic map is changed from #7 to #1.

Then, it is assumed that the slip ratio S exceeds SI at time t, immediately after map #1 is reached, and the map drop condition is satisfied. At this time, the time t is 600 m5 ec back from the slip time (tl). It is estimated that the slip occurred at time t1 due to the throttle opening (map #5) at time t1. Therefore, based on map #5, #5
By setting map #6, which has a drop of 61 sheets, it is possible to obtain a throttle opening that matches the coefficient of friction on the road surface.

In addition, in the prior art, map #l at the time of slip (1+)
Since map drop control is performed based on map #2, for example, if the throttle is closed insufficiently, it is easy to cause another slip. In this case, even if slippage can be suppressed, a subsequent feeling of acceleration will be poor.

As described above, in the driving force control device of the first embodiment, which is an embodiment of the first invention, the following effects can be obtained.

■ The set 2-θ control characteristic map is a region control characteristic map, and the opening/closing control of the throttle opening θ is based on the relative accelerator operation amount ΔL with respect to the absolute accelerator operation amount β during constant speed driving operation. Therefore, within the map area, the opening/closing control gain of the throttle valve 22 is obtained according to the accelerator work, thereby ensuring both good acceleration performance of the vehicle and prevention of large changes in vehicle speed during constant speed driving operation. can.

■ As shown in Figure 4, the ΔL-80 curve characteristic is shaped like a cubic curve, which prevents the jerky feeling when the accelerator is pressed down even slightly, and increases acceleration when the accelerator is pressed down a little. Security is achieved.

■ As shown in Fig. 7, the slip rate S is determined by the difference in rotational speed of the front and rear wheels ΔV at low vehicle speeds, so the slip rate S is calculated based on the difference in rotational speed of the front and rear wheels ΔV.
At low vehicle speeds when the slip ratio S changes, high detection accuracy and high calculation accuracy are not required, and map up control, map down control, and throttle fully closed control are performed based on the calculated value of the slip ratio S due to calculation errors. There's no chance of it happening.

■ Absolute accelerator operation amount β this time. is 2°≦2. In the small accelerator operation amount area, the currently selected area control characteristic map is maintained without changing the map, so the correspondence relationship between the absolute accelerator operation amount 2 and the throttle opening θ is stable, and the map rises. This prevents the throttle valve 20 from opening wide due to a slight depression of the accelerator pedal 20, making it possible to prevent large torque fluctuations in the low accelerator operation amount region, and to allow delicate accelerator operations. .

In addition, when starting from a stopped state of the vehicle, if 2°≦2L, the throttle opening θ relative to the absolute accelerator operation amount β is adjusted to follow the lower limit of the area control characteristic map.
The control gain can be kept to the minimum, allowing more delicate accelerator operation. − ■ Absolute amount of accelerator operation this time! . is I2L<2゜〈β8
The map upward control of the region control characteristic map in the intermediate accelerator operation amount region is performed on the condition that the slip rate S is S≦80 when the accelerator pedal 20 is depressed. The opening of the valve 22 corresponds to the accelerator operation, which reduces the discomfort felt by the driver and provides a natural feeling of acceleration.

Also, the actual throttle opening value θ. Since it is added to the condition that θ is the throttle opening upper limit value θ□8, there is no sudden increase in engine driving force.

■ Absolute accelerator operation amount this time! . In the map up control of the area control characteristic map in the high accelerator operation amount area where is 2゜≧12H, the setting time T
. Since this is performed on the condition that the acceleration continues, it is possible to obtain the high acceleration feeling intended by the driver in the high accelerator operation amount region.

Note that since the condition e0≧21 indicating the driver's intention to accelerate is added, there is no direct correspondence between the absolute accelerator operation amount β and the throttle opening θ (although the accelerator operation does not feel strange).

■ Map drop control for area control characteristic maps is performed on the condition that the slip ratio S is S>S + and FLAG-A=0. Even if the slip rate once becomes S≦S after shedding, the map up condition is satisfied or the slip rate S is changed to the newly set slip rate S1 or S.
Since the lower region control characteristic map is maintained as it is until exceeding 2, even after driving wheel slip is avoided, the driving force does not immediately return to the previous driving force level that caused the driving wheel slip, and re-slip occurs. Prevented.

In addition, if the newly set slip rate S1 is exceeded, the map will drop further, so in response to the occurrence of drive wheel slip, the throttle opening θ is controlled only in the direction of reducing the drive force, so the drive force No hunting occurs due to increase or decrease, and jerky vibrations are prevented.

■ If a slip occurs in the process of opening the throttle opening based on map up control, it is estimated that the current slip occurred due to the throttle opening approximately 600m5ec ago, taking into account the engine response delay, and the opening is calculated accordingly. As a standard, map drop control is used to drop one more plate, and in the case of excessive slip, drop two plates), so it is possible to obtain a throttle opening that matches the current road surface friction coefficient without causing poor acceleration or re-slip.

Next, a second embodiment, which is an embodiment of the second invention, will be described with reference to FIGS. 9 and 10.

To explain only the differences from the first embodiment, in the flowchart of FIG. 9, in step 102, the engine rotation speed NE is read by an engine rotation speed sensor (not shown) together with the rear wheel rotation speed V□.

Then, when the counter CTR reaches 30 through the loop processing from step 251 to step 253, step 25
The process proceeds to step 6, and the retroactive time NAGO from the time of slip is determined according to the engine speed NE. This retroactive time NAGO is set long because the response delay is large when the engine speed NE is low, and is set short when the engine speed N1 is high because the response delay is small.

In step 257, the value of MAPFLG determined a predetermined time ago in step 256 is stored as MAPOLD.

Therefore, as shown in the time chart of FIG. 10, at the time t2 when the map drop condition is satisfied, the map # is 600 m5ec earlier, which is the retroactive time based on the engine rotation speed NE (1000 rpm+m2) at that time t2.
Processing is performed to map to map #7 based on 6.
Furthermore, at the next time t3 when the map drop condition is satisfied, the engine rotation speed N t (6000 rpm
Processing is performed to map down to map #5 based on map #4, which is 100 m5ec ago, which is the retrospective time according to m).

In this way, the engine response delay is caused by the engine speed N6
By being closely related to the retroactive time NAGO
By determining this using the engine speed NE, it is possible to improve the accuracy of estimating slip occurrence compared to the first embodiment.

Next, a third embodiment, which is an embodiment of the third invention, will be described with reference to FIGS. 11 and 12.

To explain only the points that differ from the first embodiment, the 11th embodiment
In the flowchart shown in the figure, in step 102, the gear ratio GP is read from a select position sensor (not shown) together with the rear wheel rotational speeds v, 1, etc.

Then, when the counter CTR reaches 30 through the loop processing from step 251 to step 253, step 25
8, the retroactive time NAGO from the time of slip is determined according to the gear ratio GP. This look-back time NAGO is set long when the gear ratio GP is low in 4th gear because the response delay is large, and when the gear ratio GP is high in 1st gear because the response delay is small, the look-back time NAGO is set short. There is. In step 257, the MAPFL of the predetermined time period determined in step 258 is
The value of G is stored as MAPOLD.

Therefore, as shown in the time chart of FIG. 12, at the time t4 when the map drop condition is satisfied, the reference is map #4 before loOmsec, which is the backward time according to the gear ratio GP (L speed) at that time t4. Then, at time t5 when the map drop condition is satisfied, the gear ratio G at that time t5 is changed to map #5.
600m5ec which is the backward time by P (4th gear)
Processing is performed to map down to map #6 based on the previous map #5.

As described above, the engine response delay is closely related to the gear ratio GP, and by determining the look-back time NAGo based on the gear ratio GP, the accuracy of estimating slip occurrence can be improved compared to the first embodiment. I can do it.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, when determining the retroactive time NAGO,
A combination of the second embodiment and the third embodiment, that is, the thirteenth embodiment.
The time may be determined based on two-dimensional characteristics as shown in the figure, or the time may be determined based on other factors closely related to engine responsiveness, such as engine boost pressure and engine intake negative pressure. Also good.

Further, in the embodiment, an example was shown in which a plurality of area control characteristic maps having upper and lower limits were set, but linear control characteristic maps using straight lines, polygonal lines, curves, etc. may also be used, or area control characteristic maps having only an upper limit may be used. Maps may also be used.

Furthermore, in the map drop control, the rate of change of the slip rate over time may be taken into consideration, and the number of maps to be dropped may be determined in accordance with the degree of increase in the slip rate.

In addition, in the embodiment, one characteristic was shown as the ΔL-Δθ characteristic, but for example, by adding the characteristic shown in the dotted line in FIG. 4, when map #0 is selected, the ΔO is set, and when maps #1 to #7 are selected, 80 may be set based on the characteristics of the dotted line. In this case, the control gain of the throttle opening relative to the absolute accelerator operation amount may be set. It can be adapted to the driving road surface condition, and drive wheel slip can be prevented.

Furthermore, when the slip ratio exceeds a new set value, the throttle valve may be fully closed unconditionally to avoid drive wheel slip at an early stage.

(Effects of the Invention) As explained above, in the vehicle driving force control device of the present invention, when the slip ratio is lower than the set slip ratio, the current control characteristic map At the same time, each time the slip rate exceeds the set slip rate, the map moves to a higher control characteristic map with a higher increase ratio of throttle opening to the accelerator operation amount than the control characteristic map a predetermined time before. The structure includes a map selection means for selecting the control characteristic map of , which prevents re-entry lip. In addition to preventing jerky vibrations and eliminating the discomfort of accelerator operation, accurate map drop control that takes into account engine response delay quickly suppresses drive wheel slip in accordance with the coefficient of friction on the road surface, and prevents drive wheel slip. This has the effect of preventing subsequent poor acceleration or reoccurrence of slipping.

[Brief explanation of the drawing]

Fig. 1 is a claim-corresponding diagram showing the vehicle driving force control device of the present invention, Fig. 2 is an overall view showing the driving force control device of the first embodiment of the present invention, and Fig. 3 is a throttle diagram of the device of the first embodiment. FIG. 4 is a map of the area control characteristics set in the valve control circuit; FIG. The figure is a flowchart showing the main routine of control operation in the throttle valve control circuit of the first embodiment;
FIG. 6 is a flowchart showing a control operation subroutine in the throttle valve control circuit of the first embodiment, FIG. 7 is a slip rate threshold characteristic diagram of the first embodiment, and FIG. 8 is a flow chart showing the control operation subroutine in the throttle valve control circuit of the first embodiment. FIG. 9 is a flowchart showing the main parts of the second embodiment, FIG. 1O is a time chart of the second embodiment, and FIG. 11 is the main part of the third embodiment. FIG. 12 is a time chart in the third embodiment, and FIG. 13 is a two-dimensional characteristic diagram of the backward time on the other side. a--Drive wheel speed detection means b...Vehicle speed detection means C--Slip ratio calculation means d--Accelerator operation amount detection means e...Actual throttle opening value detection means f...Map Setting means g---Map selection means h---Target throttle opening value setting means 1---Throttle actuator j---Throttle valve opening/closing control means! ...-Gear ratio detection means

Claims (1)

[Scope of Claims] 1) Slip ratio calculation means for calculating a slip ratio between the tires and the road surface based on the wheel speed obtained from the driving wheel speed detection means and the vehicle body speed obtained from the vehicle body speed detection means; An accelerator operation amount detection means for detecting the accelerator operation amount, an actual throttle opening value detection means for detecting the actual throttle opening value of the throttle valve, and a plurality of control characteristic maps that set the relationship between the throttle opening and the accelerator operation amount. a map setting means for setting the slip rate, and when the slip rate is lower than the set slip rate,
In addition to shifting to a higher control characteristic map with a higher increase ratio of throttle opening to accelerator operation amount than the current control characteristic map, each time the slip rate exceeds the set slip rate, accelerator operation is performed based on the control characteristic map from a predetermined time ago. map selection means for selecting a lower control characteristic map with a lower increase ratio of throttle opening relative to the amount; and determining a target throttle opening value based on the control characteristic map selected by the map selection means and the accelerator operation amount. The present invention is characterized by comprising: target throttle opening value setting means; and throttle valve opening/closing control means for outputting a control signal to a throttle actuator to make the actual throttle opening value match the target throttle opening value. Vehicle driving force control device. 2) Slip ratio calculation means for calculating the slip ratio between the tires and the road surface based on the wheel speed obtained from the driving wheel speed detection means and the vehicle body speed obtained from the vehicle body speed detection means; and the engine rotation speed for detecting the engine rotation speed. a detection means; an accelerator operation amount detection means for detecting an accelerator operation amount with respect to an accelerator operation element; an actual throttle opening value detection means for detecting an actual throttle opening value of a throttle valve; and a relationship between the throttle opening and the accelerator operation amount. a map setting means for setting a plurality of control characteristic maps, and when the slip rate is lower than a set slip rate,
The current control characteristic map will shift to a higher control characteristic map that increases the ratio of increase in throttle opening to the amount of accelerator operation, and each time the slip rate exceeds the set slip rate, the setting will be determined based on the engine speed at that time. map selection means for selecting a lower control characteristic map that has a lower increase ratio of throttle opening to accelerator operation amount than a previous control characteristic map; and a control characteristic map selected by the map selection means and the accelerator operation amount. a target throttle opening value setting means for determining a target throttle opening value by; and a throttle valve opening/closing control means for outputting a control signal to a throttle actuator to make the actual throttle opening value match the target throttle opening value. A vehicle driving force control device comprising: . 3) Slip ratio calculating means for calculating the slip ratio between the tires and the road surface based on the wheel speed obtained from the driving wheel speed detecting means and the vehicle body speed obtained from the vehicle body speed detecting means; and a gear ratio for detecting the gear ratio of the transmission. a detection means; an accelerator operation amount detection means for detecting an accelerator operation amount with respect to an accelerator operation element; an actual throttle opening value detection means for detecting an actual throttle opening value of a throttle valve; and a relationship between the throttle opening and the accelerator operation amount. a map setting means for setting a plurality of control characteristic maps, and when the slip rate is lower than a set slip rate,
The current control characteristic map will shift to a higher control characteristic map with a higher increase ratio of throttle opening relative to the amount of accelerator operation, and each time the slip rate exceeds the set slip rate, the set time will be determined by the gear ratio at that time. map selection means for selecting a lower control characteristic map that has a lower increase ratio of throttle opening to accelerator operation amount than the previous control characteristic map; and a control characteristic map selected by the map selection means and the accelerator operation amount. a target throttle opening value setting means for determining a target throttle opening value by; a throttle valve opening/closing control means for outputting a control signal to a throttle actuator to make the actual throttle opening value match the target throttle opening value; A vehicle driving force control device comprising: